Traffic congestion and infant health: Evidence from E-ZPass

Last updated: May 2, 2011

Car emissions account for half of the carbon monoxide pollution in the United States, one third of the nitrogen oxide pollution, and 10% of fine particulate matter emissions. Areas of heavy traffic congestion — which see concentrated emissions levels in the ambient air — are of particular concern, as previous research has linked such pollution with negative effects on fetal health.

A 2011 study by Columbia University published in the American Economic Journal: Applied Economics, “Traffic Congestion and Infant Health: Evidence from E-ZPass,” compared fetal health outcomes for mothers living near congested and uncongested toll plazas on three major highways in Pennsylvania and New Jersey. The researchers focused on areas where toll plazas had instituted E-ZPass, an electronic toll collection system that allows cars to travel through more efficiently and thereby diminishes congestion and pollution. The study drew its conclusions by looking at the health outcomes of nearly 30,000 births among mothers who lived within two kilometers of an E-ZPass toll plaza.

The study’s key findings are:

In areas where E-ZPass was adopted, rates of infant prematurity decreased by between 6.7% and 9.1%; this means that, out of the sample studied, 255 preterm births were avoided.

Introduction of E-ZPass was correlated with a reduction in the incidence of low birth weight by between 8.5% and 11.3%; that means 275 cases of low birth weight were avoided.

Other variables such as changes in the characteristics of mothers living in the vicinity and shifts in nearby housing prices were checked and eliminated as possible alternate explanations for the changes in fetal health outcomes.

The researchers state that their findings “suggest that the adoption of E-ZPass was associated with significant improvements of infant health.” Given that some 1 million infants annually may be negatively affected by traffic-related pollution, the authors note, the issue of congestion has significant public health and economic implications.

If you were to rewrite the article based on knowledge of the study, what key changes would you make?

Newswriting assignments

Write a lead (or headline or nut graph) based on the study.

Spend 60 minutes exploring the issue by accessing sources of information other than the study. Write a lead (or headline or nut graph) based on the study but informed by the new information. Does the new information significantly change what one would write based on the study alone?

Interview two sources with a stake in or knowledge of the issue. Be prepared to provide them with a short summary of the study in order to get their response to it. Write a 400-word article about the study incorporating material from the interviews.

Spend additional time exploring the issue and then write a 1,200-word background article, focusing on major aspects of the issue.